Communication-enabled devices may exchange messages using various protocols. For example, a desktop or laptop computer may access the Internet using hypertext transport protocol, HTTP, run over internet protocol, IP. An end station, such as a computer or a smartphone, for example, may receive real time media content over real time transport, RTP, protocol. Protocols may be employed as a protocol stack which comprises protocols with distinct features used together. When a data stream encoded using a protocol stack is transmitted in a network, a payload portion of a first protocol data unit may comprise a protocol data unit of a second protocol, the payload portion of the protocol data unit of the second protocol in turn comprising a protocol data unit of a third protocol.
The constrained application protocol, CoAP, is a software protocol that may be employed in communication involving as at least one party a node with limited resources, such as power, processing capability or memory. CoAP allows for interactive communication with such nodes to enable them to interact with further nodes via network connections.
Networks employing CoAP may include sensor networks, for example, wherein sensor nodes may be simple, resource-constrained devices enabled to perform measurements of physical properties, or capture media such as sound. In a sensor network the sensor nodes may periodically provide measurement results they have produced, or they may be configured to provide a measurement result to a querying node responsive to a request. Such a request may be conveyed using CoAP, for example.
In networking a same-origin policy is a security concept that may be employed in browser-side programming languages, such as javascript. The policy permits executable elements originating from a network site to use each other's resources and parts. The policy may be configured to restrict use of resources and/or parts of executable elements originating from a different site.